More than 100 people have been killed in western Mosul by a March 22 explosion in a residential section of the city, military officials and an activist group say.

Brigadier Muhammad al-Jabouri, an Iraqi commander, said on March 23 that 108 bodies had been recovered after the blast in the Mosul al-Jadida district -- a district where an intense urban battle is continuing between Iraqi government forces and the Islamic State (IS) militant group.

Jabouri said the explosion was caused by booby traps that were set by IS extremists.

Mosul Eye, an independent activist organization, said IS militants forced civilians into three houses and then placed two car bombs outside while IS snipers scattered on rooftops in the area.

Mosul Eye said an air strike by an unidentified plane hit one of the cars, causing it to explode together with the explosives in the second car nearby.

Mosul Eye said 130 people were killed by the explosion, including women and children.

U.S.-backed Iraqi government forces secured eastern Mosul in January after a four-month battle.

They have been locked in urban combat since February 19 against IS fighters in western Mosul, the extremist group's last stronghold in Iraq.

The March 22 explosion comes as a United Nations official painted a bleak picture of conditions in western Mosul, saying "the worst is yet to come" for some 400,000 civilians trapped in the Old City.

Bruno Geddo, the high commissioner for refugees (UNHCR) representative in Iraq, on March 23 said people "are desperate for food. They are panicked."

He said there are now some 600,000 people trapped in west Mosul who are facing shortages of all basic needs while fighting rages around them.